L3 - Do you have the edge?

Question 1

How are discordant coastlines formed?

Answer 1

A discordant coastline occurs where bands of differing rock type run perpendicular to the coast.

Question 2

Name a hard rock type this is resistant to erosion and creates a promontory and a softer rock type which is easily eroded creating a bay.?

Answer 2

Granite and the Clays of Bagshot Beds

Question 3

What type of coastlines occur where beds, or layers, of differing rock types are folded into ridges that run parallel to the coast?

Answer 3

A concordant, longitudinal, or Pacific type coastline.

Question 4

What type of coastlines occur where beds, or layers, of differing rock types are folded into ridges that run parallel to the coast?

Answer 4

A concordant, longitudinal, or Pacific type coastline.

Question 5

What do the outer hard rock in coastlines (for example, granite) do ?

Answer 5

It’s provides a protective barrier to erosion of the softer rocks (for example, clays) further inland.

Question 6

A cove is a circular area of water with a relatively narrow entrance from the sea. But how it formed?

Answer 6

Sometimes the outer hard rock is punctured, allowing the sea to erode the softer rocks behind. This creates a cove.

Question 7

Name 4 stresses of a land slope (e.g. angle of slope)

Answer 7

• Rainwater / saturation
• Vibration, e.g. car
• Earthquakes
• Sea, cliff erosion

Question 8

Name 3 stengths of a land slope (e.g. Lubricant layers)

Answer 8

• Tree / vegetation roots
• Consolidation of material
• Porosity of soil

Question 9

Prolonged rainfall is a key factor that promotes landslides but what does it do

Answer 9

In prolonged rainfall the rainfall will saturate the soil and encourage soil movement.

Question 10

Buildings is a key factor that promotes landslides but what does it do

Answer 10

Increases weight on the slope and adds to the downward pull of gravity

Question 11

Removing vegetation is a key factor that promotes landslides but what does it do

Answer 11

Roots bind the soil together, vegetation uses up some of the moisture

Question 12

Excavation is a key factor that promotes landslides but what does it do

Answer 12

Undercutting of slope increases instability

Question 13

Permeability is a key factor that promotes landslides but what does it do

Answer 13

Water flows on surface of impermeable layer.

Question 14

Rock type is a key factor that promotes landslides but what does it do

Answer 14

Weak saturated material or shattered rocks are more likely to move than solid bedrock

Question 15

Bedrock is a key factor that promotes landslides but what does it do

Answer 15

Solid bedrock below weak materials, the junction forms the likely slide plane

Question 16

What are the main causes of landslides in the UK

Answer 16

~Weathering
~Natural erosion -by sea or river
~Artificial erosion - by railways cuttings
~Ground subsidence and removal of support
~Deposition
~Seismic shocks / vibrations
~Human induced water regime change leading to surplus water lubricating soil

Question 17

Rocks and Slopes
•Are not 1 uniform land mass •They will have hard and soft blocks of material, rock or soil etc. Which move relatively close to each other
•These blocks are separated by what?

Answer 17

These blocks are separated by joints, bedding planes or faults

Question 18

Shear stress is related to cohesion and effective normal stress as shown by which equation

Answer 18

the Coulomb-Terzaghi equation

Question 19

Mass movements occur when force exceeds resistance, give another way to name this

Answer 19

when stress > strength

Question 20

Put factor of safety, shear strength and shear stress in a equation

Answer 20

Factor of safety = shear strength/ shear stress

Question 21

How are cliffs shaped

Answer 21

Cliffs are shaped through a combination of erosion and weathering - the breakdown of rocks caused by weather conditions.

Question 22

Give an example of soft rock which erodes easily to create gently sloping cliffs. Give an example of hard rock which is more resistant and erodes slowly to create steep cliffs.

Answer 22

Soft rock, eg sand and clay,

Hard rock, eg chalk,

Question 23

Explain the process of cliff erosion

Answer 23

The process of cliff erosion
Weather weakens the top of the cliff.
The sea attacks the base of the cliff forming a wave-cut notch.
The notch increases in size causing the cliff to collapse.
The backwash carries the rubble towards the sea forming a wave-cut platform.
The process repeats and the cliff continues to retreat.

Question 24

What are slope processes

Answer 24

Movement of material down slope under the force of gravity, often involving flowing water

Question 25

Name the two main types on slope processes and how they work

Answer 25

–mass movements (downslope movement of slope material under influence of gravity only)
–water erosion (downslope movement of slope material under the influence of gravity and flowing water)

Question 26

Name 5 types of mass movement (e.g. Rockfall)

Answer 26

Rock slide 
Block glide 
Toppling failure 
Debris slide 
Slump 
Debris flow

Question 27

What is the rate of reaction in Holderness Coast

Answer 27

The average annual rate of erosion is around 2 metres per year. This is around 2 million tonnes of material every year.

Question 28

What is the bedrock at Holderness Coast

Answer 28

Under lying the Holderness Coast is bedrock made up of Cretaceous Chalk. However, in most place this is covered by glacial till deposited over 18,000 years ago. It is this soft boulder clay that is being rapidly eroded.